Electrical treatment apparatus and method of control



March 30, 1948. OFFNER 2,438,875

ELECTRICAL TREATMENT APPARATUS AND METHOD OF CONTROL Filed Nov. 27, 1941T0 ALI. HEATER) 3 patient presents to the testing current is the same asthat presented to the treatment current. Then it is clear that if E'lestbears a constant functional relationship to Ema, ITest will have thesame functional relationship to I'Ireat; that is, the ratio of ITest toITreat will equal the ratio of EI'est to E'Ireat for all values ofvoltage and patient resistance.

It is convenient to make the relationship of Emu to ETreat as nearlylinear as practicable; that is, so that the variation in the powersupplied by control device 2 will vary both ETest treatment of mentaldiseases that the resistance measured with a low value of current wasnot the effective resistance during treatment. No explanation of thiswas given, and, in fact, the opinion of experts in the art was that itwas impossible to predict the effective value of patient resistance tothe treatment current. Applicant A small deviation from linearity will,ingeneral,

give slight and insignificant changes in' the results. Y

A simple illustration of the above principle is ment voltage is appliedapparently 1s due to the change in the polarizable nature of the tissuesillustrated in Fig. 2. Here the power is derivedfrom an alternatingcurrent supply, and a variable autotransformer is therefore used at 2. 3and A are replaced by a tapped transformer ll. I-Iere the treatmentvoltage is supplied by the full secondary of II; thatis, the voltagebetween points [2 and I3. The testing current, on the other hand, issupplied by the voltage between l2 and the secondary tap l4; thussupplying a smaller alternating current voltage for testing.-- Meter 8is now an alternating current milliammeter I 5; meter I6 in place ofmeter I0 is a similar meter, but of higher range. The switches! and 9are replaced by a double throw switch 11. when this is thrown to contactl8, the' testing circuit is connected to the electrodes 5 andB and whenat [9, the treatment circuit is connected to the electrodes.

Adjustable resistors and 2| are introduced respectively into the testingand treatment circuits. The relative values of these are adjustedsothatthe total internal resistance in the two' circuits is as nearlyidentical as possible. These resistors also have another function; byintroducing the resistor 2| intothe treatment circuit, and having saidresistor large as compared with the effective patient resistance whichwill be inserte d between electrodes 5 and 6, the effect of smallvariations in said patient resistance is minimized. 7

Because of the linear relationship between the test and treat voltages,the treatment current will always bear the same relationship to the testcurrent. The test current meter may, therefore, be calibrated not interms of the actual test current flowing, but rather in terms of thetreatment current which will flow. That is, it will be calibrated toread Treat Tc-t X 1TB Then when the switch I! is turned to point I8 fortesting, the variable transformer 2 may be adjusted until meter l5 readsthe desired value of treatment current. Throwing switch I? to l9 thenwill apply this actual treatment current through the electrodes. Thus,it is seen that the. voltage is adjusted to the proper'value as would bedetermined by application of Ohms law, but no actual calculation isnecessary. This is taken care of automatically by the construction ofthe apparatus.

The use of the apparatus of Fig. 2 assumes that the resistance of thepatient to the power line frequency is the same for the testing currentas for the treatment current. It was, however, discovered early in theart of electric shockhas, however, discovered a means for predicting theeffective rsistance of the patient to the treat ment current beforeapplication of said current. This then allows the voltage to be set tothe proper value to give the desired value of treat- ;1 nent current. V

-; .;Applicant has discovered that the apparent changein the patientsresistance when the treatthrough which the current flows. Referring toFig. 3, the normal tissue may be considered roughly equivalent to acondenser 22, shunted by a resistor 23, the whole being in series withanother resistor 24. The two terminals 25 and 26 represent the points ofapplication of therelectrodes with which these electricalcharacteristics are measured. For low frequencies such as cycles persecond, and for low intensities of current, the effective reactance of22 is large, as is the resistance 23, as compared with the'resistance24. Representative values would be 22 equals /2 microfarad, orapproximately 5200 ohms reactance. .Resistance 23 equals'approximately1000 ohms. Resistance 24 equals approximately 120 ohms.

It will thus be seen that at frequencies of the order of 60 cycles,almost all the voltage drop is a result of the parallel combination of22 and 23. rent is applied, this excites the tissue under theelectrodes, and results in a substantially complete short circuit ofcondenser 22.. This may be -represented as resistor 23 falling to a,very low value, approximately 80 ohms'.. Thus resistance-24 is mosteffective in limiting the value of the treatment current, whileresistance 23 also has some effect.

Applicant has also discovered a method of predicting the change. This isaccomplished by measuring the resistance not with the low frequencycurrent to be used in treatment, but rather with a relatively highfrequency current; If the frequency is high enough, it will evidently gothrough condenser 22 almost unimpeded, and the effective resistancemeasured would be that of resistor 24 alone. .If' a somewhat lowerfrequency is used, condenser 22 will stillpresent some'reactance, andthe frequency may beiad- .l'usted so that the'effective impedance isthat presented during treatment; that is, the impedance of 22 and 23 inparallel should add approximately ohms to the total impedance presentedbetween terminals 25 and 26. This is accomplished by'using a frequencyof approximately 7000'cycles per second for the testing current. Thefrequency used is, however, not at all critical, especially in thecircuit used in which a resistor is placed in series with the patient,similar to resistance 2| of Fig. 2. This is described in greater detailbelow.

This principle of using a high frequencycurirent for testing thepatients resistance could be employed by using ordinary resistancemeasurements for determination of this high frequency resistance,subsequentlyv adjusting the treatment voltage, as determinedbyzapplication of Ohms law. However, a more convenient methodisf the-I-Iowever; when the intense treatment curaccuse-u applicatior-r of a--circuit simi-lan to th-at ofFig; 1.

To employ thisprinciple with thiscircuit thus eliminatethe-needlor-calcrflationa devices may consist; of an"oscillator-generating the desired frequency for-testingzas above-stated;ap-

proximately 7000' cycles per second-:- Thevoltage supply of;thisoscillator-is derived fromvoltage control-device Z=-so-- thatvoltage-at the: test frequency isproportionahtothewoltage suppliedDevice -4 k may then be a transformer to change the powerinput voltage*to the desired voltage. A-meter capable -of=-respondingtahighfrequencytest currents of smal-l amplitude is used at 8,whereas-anordinary A .-C'. ammeter or mil liammeter-may beused-at I 0 Asdescribed above; the internal; resistance of; the-test and: treatcircuits must be adjusted-to equality. Thismay beaccomplished by havingresistors in devices 3 and 4* for makingsuch adjustment; thisis-explained in greater: detail below. Meter 'S may again be calibratedto read} thetreatment current directly so that--in-use the electrodes-Sand 6* may he placed on the patientandcontrol-2' adjusted so-thatwith- Fclosed-"8 Willread the desired treatmentcurrent; on opening l" andclosing 9,; the treatment current Wi-lPthflnflow ou hthe a en The wiringdiagram of a complete instrument A yoltmeten 4t isconnecteditbaiead thevolte age existing across th treatmentizelectrodes; it.

maybe used'to register the value of the applied potential;

employing the principles describedaboveis shown in Fig. i.Thisiillustrates aninstrument for providing known current-oi the powerline frequency, for known intervals oftim through thepatient. The powerline current, as for example 115 volts sixty cycle alternatingcurrent,is suppliedat the terminals 21,18." The control device 2' of Fig. 1 ishere a-variableautotransformeriil.

Thissllpplies a, variable voltage to the primaryof transiiormer 31; Thesecondary 3 2 of i this transformer supplies the power for-thetreatmentof the patient. v The power-for the testingcircuit is also derived fromthesecondary of this transformer. This is a somewhatdifferent-arrangement than that shown inFig; l, thepowenbein takenfromrthe secondary forthepurposes ofutilizing the electricalisolating-propertiesof transformer 3|. Following thepa-thof thetreatment current, it is seen that-saidicurrentnext flows milliarnmeter38 thence through one set of con tacts 39a, of the test switch 39 whichwill bein1 the out position; and thence to one treatment. electrode all:

ground to the lower side of the secondaryltz of transformer-3 I.

Overload relay having co-il and contacts .18;

Thereturn circuit is through. ground u passing from= electrode- 41;through.

A power supply unit? fi' suppliese directscurrent power for operationofthe timer circuit: and: or; the test meter circuit; ltrconsistsx0f='trans0rmer 46 having primary 41 connected acrossathe power:

line, a-center-tapped voltage winding. 48';

a rectifier filament: winding 49; and& a: heater current winding 50 foroperating the; heaters of all other vacuum tubesdn the i. apparatus;Therectifier 5| rectifies the high voltageanda condenser 'iz smooths thecsci liationsimthis voltage.

Resistor 53 which i is shunted? across the power supply allowstheselectionof proper-voltages for a timer tube 54;

Theoperationof the timeeisias-ifollowsz the. coil 34' of the timerrelayisintheepl'ate circuit of vacuum'tube" 54;- Thecathode circuit. is; reaturned to a point onmesistor -53- su fficiently posia tive that no platecurrent normally flows-.thrOugh coil 34'; Variable resistorqlifiwhi-chis constructed of i a switch selecting alnumber orfixedzresistors,

isconnected betweerrthe grid .,of'5.4'sv andiground,

the latter being alsothermostclnegative pointzrloi testing; switch. 359:is

power supply 45: pushed in, and): contact 39b connects; condenser 56 totheglpositive side O r-power; supply 451 When switch 39 is:released',icondensers5fiire mains charged: to this voltage; When treatment switch36 is closed; condenser-s 55115 connected.

through contacts iifib to the-gridfofri54,bringing the latter toalpositive-glpotential, andzallowing platecurrent to now throughcoil134l; Thiszrew sults in the contacts-1331 closing; andvthusicloseslthe: treatment tcircuit. Condenser 56'. almostin stantane ouslyadischarges'througlr thejgridrcircuit of 54 to apointzwhere its; voltageis equalto:

the cathode voltage.- of 54".: It subsequently 'dis charges more slowlythroughlresistor 55, andieventually the grid potential.oi"54ibecomessoclow that the plate current is insufficient to energizethe.

coil 34 and hold. contactsn33scloseda; They will then open,terminating;the;flowoil-treatment current. It will be seen thatagreatrrange Qf'tirnes maybe achievedtbyr varying the resistanceof; 55.

It will also beseen that the opening of switch 36 will terminate thetreatment imt-womanners: first, by causing-thetimer relayr toopen'pthrough.

the opening ofcontacts, 36b; and secondly, by

opening-" the. treatment currenti directly; by the opening of thecontactsof 350;. Thus; dual, con-- trol is had over-the flow oftheatreatmentccurrent, and if for any: reasonatheitimer did not;

terminate the treatment; at r the desired :time, ,it may be immediatelyterminated: by release of. switch 36; This prevents anoverly'longrtreata ment which might occur if, for. example thecontactsof relay 33should, stick togethen;

Anothersafety feature is that: when icontacts 3611 are in the outposition, theoutput o-f-the treatment circuit is short-circuited:v If"thl'lfor any reason the timer circuit "should stay closed, withouthavingthe: treatment switchwpushed in; and autotransformer 29 should'b'eadvanced to the point where appreciable voltageis developed bytransformer 3|, a large current will-flow. through coil 35 of theoverload-relay; causing-it m open the circuit. This then-preventsth'einstrument from being-used when the timer-circuit 15511101331'3- tive.

The, testing circuit 51 consistsofi oscillator tube 58, transformer 59';which has" a: tapped primary 60; and secondary 61*; a plate blockconde'nser 6'2;

" oscillatory 'circuitcondenser 63, grid leak 64, and

condenser 65 and shunt feed. resistor 66. It will be seen that this isthe familiar Hartley'oscillator circuit, with the frequencyapproximately determined by the inductance of primary 60; and condenser63. For the present purposes this is best adjusted to, approximately7000 cycles per second. The secondary iii of the transformer '59 isloaded by means of resistance 61; the purpose of this is to make thiscircuit have an almost pure resistive impedance, so that the resistanceof the test and treat circuits may be equalized, as mentionedpreviously. As th plate voltage of 58 is supplied through resistor'66from the secondary 32 of treatment transformer 3|, said plate voltagewill be nearly proportional to said treatment voltage. Likewise, thevoltage appearing at the terminals of secondary 9| will alsobe cl selyproportional to the voltage of said treatment transformer- Thus thelinear relationship between testing voltag and treatment voltage ispreserved, as required.

Resistance 68 isinserted in series with the testing voltage in order tomaketthe resistance of the testing circuit equal to that of thetreatment circuit. It thus is similar in function to resistance 31 ofthe treatment circuit and will usually be of almost the same magnitude.Resistance 68 performs another function: it provides a source of voltagedrop proportional to the testing current. Said voltage drop is measuredby a Vacuum tube microammeter, to be described below, thus giving themagnitude of the testing current.

The path of the testing current is as follows: when switch 39 isdepressed thetesting voltage is induced in secondary 6! of transformer59 by oscillator 51. The voltage developed across resistance 61 causes acurrent to flow through the contacts 39a of switch 39; thence to patientelectrode 49, through the patient, through electrode Al thence toground; thence through resistance 68 and thence back to the'secondary 6!of transformer 59.

The Vacuum tube microammeter 69 consists. of vacuum tube 19, acombination diode and triode. The bias voltage for said triode isfurnished by cathode resistor H, which is" bypassed by condenser 12, Theplate voltage for said triode is supplied through plate couplingresistor 13 from the positive side of power supply 45. It will be seenthat the triode unit of IO thus amplifies the voltage appearing acrossresistor 68, due to the passage of the current, and, said amplifiedvoltage appears across resistor 13, This voltage is coupled into thediode circuit by means of condenser i l, The diode circuit consists offixed resistor 15 and variable resistor 15 in series with D. C.microammeter '11; all being acrossthe cathode and diode plates of iii.The alternating current voltage induced in this circuit throughcondenser 14 causes a rectified current to flow through the diodecircuit, giving a reading o microammeter i? closely proportional to theamplitude of said alternating current, Vacuum tube microammeter 69 iscalibrated so that its reading for a given testing current willcorrespond to the desired value of treatment current. This isaccomplished in thefollowingmanner: electrodes) and ll may beshort-circuited, or a resistance of the order of magnitude of thepatients resistance may be placed between said electrodes. In eithercase, the testing switch 39a is momentarily depressed, in order to setthe timer. Sufficient resistance is introduced by resistance 55 into thetimer circuit so that the timer will remain closed fora considerablelength of time; for example, 10 seconds. depressed causing treatmentcurrent to flow. Its magnitude is noted on milliammeter 38, and variabletransformer 29 is advanced until this current is of some desired value;for example, 500 milliamperes. Test switch 39 is now depressed, andassuming that the scale of microammeter T! has been calibrated to readthe treatment current directly, resistance 18 is adjusted untilmicroammeter i1 registers the same current as was registered onmilliamrneter39. Now in use it is only necessary to first press the testswitch 39; adjust transformer 29 until microammeter 11 reads thedesiredcurrent; then depress switch 36, whereupon the desired treatmentcurrent will be giventhe patient. Thelength of the treatment is, ofcourse, controlled by the timer; this is started when the treatmentswitch 36 is depressed, and interrupts the current after the intervalpre-set by means of resistance 55.

Resistance 31, which is in the treatment circuit, is variable and is,adjusted in the following manner: electrodes 49 and M areshort-circuited, testing switch 39 depressed, and the variabletransformer 29 adjusted so that some given reading is registered onmicroammeter 11. The treatment switch is now depressed, with testingswitch having been released, and the treatment current read onmilliammeter 39. The treat switch 36 is now released, and a resistanceintroduced between electrodes 49 and 4|. This resistance may be of theorder of magnitude of the patients resistance. The above procedure isagain carried out, the microammeter 'l'i being brought to the samereading as before by adjusting 29, and the reading of 38 is again noted.When the adjustment of resistance 37 is correct, this will be the sameas before. If it reads more than before, this indicates thatresistance-31 is of too high a value, and should be reduced; andvice-versa.

It will be seen that when testing switch 39 is depressed, the treatmentcircuit is interrupted by the opening of o-ut contacts 39a, Thisprevents a simultaneous-application of the testing and treatmentcurrents, which might not only be injurious to the patient but to theinstrument as well. 7

As before described, it is necessary to press the test switch 39 tocharge the condenser 56 in order to make the timer operative. This thusinsures that the test reading will be made before the treatment isgiven, and is a safety feature of the instrument.

In the specification, the principles of the invention have beendescribed as applied to a medical therapeutic device, and it has beenespecially used in the production of convulsive shock in the treatmentof mental disorders. It has been particularly useful in this fieldbecause of the very close control of the treatment current which itprovides. However, these principles can beapplied in other fields, andespecially wherever it is necessary to set a current to the desiredValue before the application of the full strength of current; and 7 alsowherever the electrical characteristics of the medium through which thecurrent isto .be appliedapproaches those described above as being thecharacteristics of living tissue The invention is, therefore, notlimited to the particular uses and embodiments described for the purposeof illustration, but is of broad scope as defined by the followingclaims. 1

The term circuitfas used'herein is intended Treatment switch 39 is now 9to denote a conductive part or a system of conducting parts throughwhich current is intended to flow.

I claim: 1. The method of preselecting the magnitude of a low frequencytreatment current which comprises passing through a subject to betreated a test current having a frequency of the order of 7000 cycles,measuring the effective impedance of the subject to the test current andad-' justing the test circuit and treatment circuit simultaneously andproportionately to a value of the test current having a predeterminedrelationship to the desired value of the treating current.

2. The method of preselecting the magnitude of a low frequency treatmentcurrent which comprises passing through a subject to be treated a testcurrent having a frequency not materially less than about 7000 cycles,measuring the effective impedance of the subject to the test current andadjusting the test circuit and treatment circuit simultaneously andproportionately to a value of the test current having a predeterminedrelationship to the desired value of the treating current.

3. In electrical treatment apparatus, a low frequency current source,current supply adjusting means connected to said low frequency currentsource, current applying electrodes, means including a current measuringdevice and a timing means connecting said current supply adjusting meansto said electrodes, means connected to said current supply adjustingmeans for converting the low frequency current to high frequencycurrent, means including a second current measuring device forconnecting said current converting means to said electrodesindependently of the low frequency current connecting means, andvariable impedance elements for calibrating said second currentmeasuring device in terms of the low frequency current indication ofsaid first current measuring device.

4. In an electrical treatment apparatus as defined in claim 3, means inone of said (low frequency and high frequency) current connecting meansfor adjustment of the internal impedance of said low frequency and highfrequency current connecting means to the same value.

5. In an electrical treatment apparatus as defined in claim 3, animpedance in said low frequency current connecting means having a highervalue than the value of the impedance of the subject under treatment,whereby the effect of small changes in the resistance of the subject isdecreased.

6. In an electrical treatment apparatus as defined in claim 3, saidmeans for converting the low frequency current to high frequency currentincluding a vacuum tube oscillator circuit.

7. In an electrical treatment apparatus as defined in claim 3, saidsecond current measuring device including an impedance in said highfrequency current connecting means, an electron tube amplifier foramplifying the voltage developed across said impedance, and means formeasuring the intensity of said amplified voltage.

FRANKLIN OFFNER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,761,476 Hathaway June 3, 1930Re. 15,469 Heising Oct. 17, 1922 1,667,451 Arnberg Apr. 24, 19281,820,242 Neimann et al. Aug. 25, 1931 2,111,135 Bagno 'Mar. 15, 19382,184,511 Bagno Dec. 26, 1939 2,311,935 Dobert Feb. 23, 1943 FOREIGNPATENTS Number Country Date 574,433 France Mar. 29, 1924 554,559 GermanyJuly 11, 1932 157,009 Austria Sept. 25, 1939 158,595 Austria Apr. 25,1940 239,085 Germany Oct. 7, 1911 OTHER REFERENCES An ElectronicInterrupter, by I James H. Hanly, published in Electronics for November1935.

Marton, superfluous Hair, from Medical Record for February 19, 1936,page 153.

Kovacs, Electrotherapy and Light Therapy, 2nd edition, 1935, pages 149and 150.

Electric-Convulsion Therapy in Schizophrenia, by Lothar Kalinowsky, M.D., pp. 3-8 (reprinted from Dec. 9, 1939, issue of The Lancet, p. 1232).

Cerletti et al., Bull, Acad. Med. Rome, May 1938, pp. 266-68.

Cole 8: Curtis, J. Gen. Physiol (1939), vol. 22; pages 37-64.

